Expert: Tom Whiting - 8/13/2010

Question
I know very little about astronomy. I have a star chart which
only confuses me. Looking NE I see a star which seems to have
red,blue and white color and sparkles like a diamond. It is
beautiful. I would like to know what this star might be. It is
about10 o clock position around 11:PM in North East.

Answer
Hi Dave,
You failed to give me a location and time zone so I'll just have
to work off the compass direction for August 12th... realizing there is one hour (sky) difference (rising time)  between the eastern side of a time zone and the western side of a time zone.

I'll give you 2 bright objects so you can decide what you are seeing, with EXACT compass directions...the super-bright planet Jupiter now rises DUE EAST at around 10 pm.  The bright star Capella (Alpha Aurigae) rises in the ENE around 11 pm. along with the relatively bright star Fomalhaut in the SE sky at almost the exact same time for 40 degrees N. Latitude.

Stars are more subject to twinkling than planets.  All that twinkling, swelling, fading, sparkling, etc...  In fact ANY deviation from the normal, steady, constant color and shape... IS all atmospherics.  You are seeing the effects of what our
atmosphere does to stars and planets. (Color and brightness changes very rapidly, called sintillation or twinkling).  Check that same object out again, say 2 hours later when it's 30 degrees high, and you'll find that all those atmospheric effects are nearly gone, or highly diminished.  That's the best I can do with what you gave me.
You can check it again tonight, as they rise 4 minutes earlier than
last night, every night.
Clear Skies,
Tom Whiting
Erie, PA
PS... right now, August 12 and 13,  most people are outside watching the Perseid meteors from the NE beginning around 11 pm, rather than atmospheric-caused... twinkling stars and planets.